TS, Equivocator:
That's right, the 400M is markedly quieter than e.g. the Transall. A bit more noisy maybe than the A380. The sound itself is kind funny, all chaotic and out-of-tune when idle on ground, but in flight it's just a loud buzz. A very big, dark bumble bee!
(Or should that be the Airbus Tumbledore entry for the "name the A400M" thread?)